Blow plastic bucket can be fundamentally divided into two categories: Extrusion - blow molding and injection - blow molding. The main difference between the two is the preparation of preform and the blow molding process is essentially the same. In both approaches the foundation formed to carry out up there on: Extrusion - Stretch - Blow (referred to squeeze - pull - blown), injection - Stretch - Blow (referred to Note - pull - blown), and multi-layer mapping plastic and so on.
Injection - Blow (referred to Note - Blowing) Plastic bottles are first used plastic injection molding parison bottom, then move the hot parison blow mold blow molding of hollow products. Note - Blow container has no flash, good dimensional stability, the mouth and thread quality, parison thickness can be pre-conditioning products, cosmetic packaging gloss, and thrifty raw materials. But note - blow molding of large and complex shape inappropriate consumption of container, but also due to the use of injection and blow mold two, so a larger investment in equipment. Note - Blow the container to form a small bottle of single barrel main body, it can use PVC, polyethylene, polypropylene and polystyrene, polyester, polyamide resin, etc. to consumer. Mainly used for medicine, food, cosmetics and other packaging for the type of hollow plastic blow molding of polyethylene, polyvinyl chloride, polypropylene, polystyrene, linear polyester, polycarbonate, polyamide, cellulose acetate and polyacetal resin.
The cost of which accounts for high-density polyethylene top. It is widely used in food, chemicals and disposal of liquid packaging. High molecular weight polyethylene for the manufacture of large fuel tanks and barrels Cuo. PVC due to better transparency and air tightness, so washing agent in cosmetics and packaging are universally applied. With the non-toxic PVC resin and additives development, and stretch blow molding technology to carry out, PVC food packaging containers moving rapidly to increase the amount, and once other start for the beer and drinks containing carbon dioxide packaging. Linear polyester materials into the hollow blow in recent years new areas of information. Because of its products with a shiny appearance, excellent transparency, high mechanical strength and storage of goods in containers better combustion disposal of waste does not pollute the environment, the advantages of bottle carried out by so quickly, particularly pressure area in the use of plastic food containers is most common. Modified polypropylene resin and process for its technology, the use of volume increased year by year.
Main raw materials and the typical formula
(L) polyethylene melt index for the ordinary use of polyethylene resin l ~ 6.
(2) polypropylene mesh melt index for the general election 2 to 4 of polypropylene resin.
(3) selection of general-purpose polystyrene or erosion common type of injection grade polystyrene resin.
(4) rigid PVC transparent bottle formula in Table 1.
Plastic bucket and characteristics of major equipment production
(1) and ordinary extruder and extrusion head - blowing the same basic equipment.
(2) install the parison extruder disposed tubular parison, to go through the installation to stop off at the bottom and neck fusion process, made test-tube-shaped parison bottom.
(3) installation of preform heating installed preform heating oven, heating the sleeve, heating and other channels, heating electric heating or infrared heating can be. But to be able to install heating and balanced heating thermostat, so to minimize the temperature difference between inside and outside of preform.
(4) tensile bars and tensile stretch installed two fixtures.
① stretch stretching mandrel into the mandrel from the upper parison, the parison to withstand the hydraulic effect of the bottom, to stop the vertical stretch, and then pass into the pores on the mandrel air blows up tight to stop the radial stretch.